-1/5r-2r=-11

Solution for -1/5r-2r=-11 equation:

-1/5r-2r=-11

We move all terms to the left:

-1/5r-2r-(-11)=0


Domain of the equation: 5r!=0

r!=0/5

r!=0

r∈R


We add all the numbers together, and all the variables

-2r-1/5r+11=0

We multiply all the terms by the denominator


-2r*5r+11*5r-1=0

Wy multiply elements

-10r^2+55r-1=0

a = -10; b = 55; c = -1;
Δ = b2-4ac
Δ = 552-4·(-10)·(-1)
Δ = 2985
The delta value is higher than zero, so the equation has two solutions
We use following formulas to calculate our solutions:
$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}$

$r_{1}=\frac{-b-\sqrt{\Delta}}{2a}=\frac{-(55)-\sqrt{2985}}{2*-10}=\frac{-55-\sqrt{2985}}{-20}
$
$r_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{-(55)+\sqrt{2985}}{2*-10}=\frac{-55+\sqrt{2985}}{-20}
$